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Hartzell Propeller Appliation Guide
I was looking for the aluminum Hartzell limitations (RPM/MAP) for different prop hub/blade models and engine combos, and found this link. The Vans section starts at Chapter is 61-02-59, page 1423 (PDF number) to 1442.
http://hartzellprop.com//services/pr...ication-guide/ Direct Link to PDF. https://hartzellprop.com/wp-content/...59-0000-WA.pdf I called Hartzell and asked them a few questions. The main take away is to keep in mind some prop (hub/blade) models and engine models with electronic ignition have not been tested. For those who remember before the BA prop came out Hartzell tested their standard CS prop for 180 HP Lycs (HC-C2YK-1BF/7666-2) with electronic ignitions and found some undesirable vibrations at certain RPM/MAP settings and set a life limit. That lead to the BA 7496 prop. It was better but still had some RPM/MAP limits on non-dampened cranks. Than the BA 7497 blade came out with no restrictions. Keep in mind that not all engines have been tested with electronic ignitions of every possible combinations. If in doubt call Hartzell. Any one want to chime in with trivia and fun facts. Does anyone have any direct comparison of the BA 7496 vs BA 7497 performance? |
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TCDS link: http://rgl.faa.gov/Regulatory_and_Gu...-920_Rev39.pdf See Page 8, "Note 9: Special Limits: Table of Propeller – Engine Combinations Approved Vibrationwise for Use on Normal Category Single Engine Tractor Aircraft". However, note this at the top of page 8: "The maximum and minimum propeller diameters that can be used from a vibration standpoint are shown below. No reduction below the minimum diameter listed is permissible, since this figure includes the diameter reduction allowable for repair purposes. |
Thanks Carl.
Az_gila it's experimental aircraft so you can do what you want. Hartzell is covering their Six O'clock. The good news Hartzell has tested several common prop/eng combos with electronic ignitions on RV's. One can extrapolate or interpolated. It's on the builder in the end. My feeling always has been if you have a custom fire breathing maxed out turbocharged high compression electronic ignition Frankenstein engine, you might want to go with a composite prop, which is more forgiving with harmonic vibrations and fatigue. Hartzell has a nice composite prop, but it's expensive. |
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TC (Link Carl Posted below) for the Prop Hub (and blades and approved engines), if you read it like a Philly Lawyer, there is a slim chance [my opinion] you have a "certified" combo unless you strictly adhere to all the flag notes, especially 9 and 10, stock Lycoming & Prop combo with approved Governor, certified ignition, exhaust, airbox and no changes of any kind from stock engine and installation of said engine in certified plane..... Note 10 states the combo must have been part of a certified airplane approval. One might argue Hartzell tested Engine/Prop Combo on RV's. RV is not a certified plane. Again up to you to make the case. The Hartzell Application guide is GOOD INFO for RPM/MAP restrictions along with the TC. If you find the combo in the TC and certified plane TC, e.g.: Piper Arrow, Mooney you have a case. I have (had) a "Mooney" combo Engine and Prop, but it went out the window with electronic ignition and 4-into-1 exhaust. Again convince FAA/DAR you are a "certified combo" good to go for 25 hours Phase 1. Personally it does not matter and I want freedom to add custom exhaust, ignition, prop Gov of my choice...... etc. http://rgl.faa.gov/Regulatory_and_Gu...-920_Rev39.pdf |
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As one other data point for the RV-10, I wholly recommend the 2 bladed composite (8301) blades and the "B" hub! I checked the document, and did not see it listed. Before I bought my propellor (through Van's), I talked to an engineer at Hartzell about it quite a lot, because I was worried about the AL blades with my engine. I have 10 to 1 pistons and dual electronic ignitions (LSE's). The engineer told me that the 8301 blades would be a great match for the 10. Kahuna had done extensive testing for Hartzell with the strain gauges, and data collecting on his 540 and the 2 bladed composite and TRIED to tear them up, and the combination was bullet proof. The Hartzell guy said no worries with the high compressions pistons and no RPM restrictions. Also this prop is anywhere from 8 to 11 POUNDS lighter than the AL blades. I have 170 hours on the plane so far with no complaints on the combination. It's been great. |
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Larry |
Hartzell Propeller Appliation Guide
My IA buddy, who helped me build, told me the minute I hung the certified engine on my -9A, it became experimental. The FAA inspector agreed, saying Van's aircraft were not on the engine's original certification document. An interesting note though, the inspector said there are two ways to return it back to a certified engine; (1)an IA must certify no experimental modifications and all ADs are complied with, OR (2) sent it to certified shop for complete overhaul. Dan from Reno
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Bottom line the type certificate for the prop as a very generic note saying ANY CHANGE can affect the prop operations. How the prop vibrates (or dampens vibrations) for a specific configuration and causes metal fatigue is the issue. Keep in mind they have lots of safety factors and margins on the prop and blades. Back in the day people took fixed pitch metal props, cut them down, re-pitched the heck out of them. They had lots of fixed pitch metal prop fatigue failures. So it was a thing. Sensenich sells safe metal fixed props for the RV fast kit plane market now.... You'd be crazy to mod a fixed metal prop like that today, especially with so many good composite and wood props which are virtually fatigue free (but are subject to environmental damage). My opinion is FI vs Carb is not a big driver, except if it makes more HP. We have very free flow intake and exhaust which adds power. Cross Over vs 4-into-1 Pipes, Magneto vs Electronic Ignition, Compression ratio Low vs. High, Non counterweight crank vs counter weighted crank, are all players in how the prop vibrates (due to power pulses and size of that pulse). If you can find something close you are good. The fatigue life on these props is pretty long. Just avoid the yellow band RPM's of the configuration that is close to yours and you will be safe. |
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